In a tire manufacturing plant, tires molded in rows of tires presses are deposited on a trench conveyor and transported to an inspection, balance, or trim station. Because trench conveyors are typically positioned below the presses at a relatively low elevation, incline conveyors are used to elevate the tires received from the trench conveyor to the level of the presses or higher for transport to subsequent finishing stations. Belt conveyors, such as modular plastic belt conveyors with high-friction conveying-surface characteristics, work well on shallow inclines. On steeper inclines, however, belts with conveying surfaces textured with inverted cones or other non-skid protrusions work well when new. As the protrusions wear, tires begin to slide down the conveying surface as the belt advances up a steep incline. Rubber-topped belts are not so susceptible to wear, but the slippery mold-release material used to ease ejection of the tires from the presses coats the rubber conveying surface of the belt, which then loses its effectiveness as a high-friction surface. Consequently, incline angles are limited to a maximum of about 25° off horizontal. Such shallow inclines have a large footprint, taking up valuable floor space. Even if tires could be prevented from sliding along the conveying surface on steep inclines, there must be provisions to prevent tires from falling away from the belt. A wall or other static structure in sliding contact with high-friction articles, such as tires, being lifted on the incline may damage the articles and will increase the load, requiring an oversized belt and drive system.
In tire warehouses or stores and service stations stocking large numbers of tires, the tires are usually stacked to great heights. Further, the tires may be stacked on shelves or second levels and thus begin to be stacked at heights over 6 feet. Conveyors may be used to elevate the tires to the level of the tire storage or higher for transport to additional floors. Traditional conveyors use friction or protrusions to prevent the tires from sliding down the inclined conveyor or from falling off of the side of the conveyor belt. However, friction and protrusions are not fail-safe methods and tires often fall off of the conveyor causing harm to people and property located near the conveyor.
The tire distribution process often includes transporting large quantities of tires from the plants where they are manufactured to the various facilities where tires are delivered to consumers and/or mounted on vehicles. The processes for transporting tires from these plants to wholesalers, retailers, and service centers typically involve the use of large vessels. For example, semi-trailers are used for transportation over the road, rail cars are used for transportation via rail, and shipping containers are used for transportation over water. Further, these vessels often provide storage of tires prior to and after transport.
To minimize the costs associated with such storage and transportation, it is desirable to pack tires into each storage and/or transportation vessel in such a manner as to maximize the density of tires within the vessel, while providing satisfactory stability of the loaded tires and avoiding permanent deformation of the loaded tires. Maintenance of tires under a compressive load has been found to improve the stability of the loaded tires. However, compression may lead to permanent deformation of tires in some stacking configurations.
Additionally, to minimize the costs associated with storing the tires once they arrive at their destination (e.g., facilities where tires are delivered to consumers and/or mounted on vehicles such as warehouses and car repair shops), it is desirable to pack tires into the storage location in such a manner as to maximize the density of tires within the storage location, while providing satisfactory stability of the stored tires to prevent injury and save space and avoiding permanent deformation of the stored tires, which may be stored for months or even years.
When the storage and/or transportation within the vessel is complete, tires are typically manually unloaded from the vessel onto a conveyor or pallet. A variety of implements exist for such handling of tires. For example, U.S. Pat. No. 3,822,526, issued to Black in 1974 and incorporated herein in its entirety, discloses a device for manipulating tires. However, a device does not exist that sufficiently eliminates the difficulties of manually stacking tires in a storage and/or transportation vessel, and unloading the compressed tires from the same vessel. Moreover, no sufficient device currently exists to eliminate the reliance on the vessel to maintain a compressive load on tires. Although loaders for tires exist, for example, a machine loader and a loader to create a straight stack of tires, the existing loaders are not designed to stack tires in a herringbone pattern. Further still, the current practice is to rest tires directly against the wall and floor of the trailer or boxcar. As a result, the weight of the stacks is unevenly distributed causing further compression and strain on tires. Thus, a lower-compression system for cradling tires during storage and shipping is desired.
Belt conveyors for tires have been produced to transport tires up to various heights. See U.S. Pat. Pub. No. 2008/0053796 to DePaso et al. (“DePaso”). The entire disclosure of DePaso is incorporated by reference in its entirety.
Thus, there is a need for an elevating conveyor capable of transporting articles, especially tires and solar panels, up steep inclines. Additionally, there is a need for an elevating conveyor capable of transporting large tires, such as tractor trailer tires and tractor tires, and solar panels.